Traditional hitch receivers generally are constructed of welded steel tubing and profile cut flat plate. Steel has long been the material of choice due to its availability, low cost and knowledge in how to work with it.
Referring to FIG. 1, the diagram illustrates a very common ball and socket type of hitch mechanism that has been in use for many years. The ball (10) is mounted either to the hitch frame (40) or to a removable bar (20) that fits into and is pinned to a tube (30) integral to the hitch frame. The socket housing (50) is connected to the trailer and contains a lever (51) to pull a locking mechanism up under the ball (10) once connected. Two safety chains (52) are connected to the socket housing (50) and are manually clipped to the vehicle hitch frame (41). The electrical connection is manually made with a multi-conductor connector. One side of the connector (26) is on a cable wired to the trailer and the other side of the connector (25) is wired to the tow vehicle.
Hitch configurations of many types have been constructed ranging from ball and socket arrangements for light duty applications to heavy-duty fifth wheel arrangements used on transport trucks.
Referring to FIG. 2, the diagram illustrates a common fifth wheel hitch that has been in use for many years. A hitch frame (80) is attached to the body of the truck and supports the hitch mechanism (90). A ramp and skid plate (91) is used to guide the hitch pin (92), mounted on the trailer frame (93), into a retaining slot (94). Under the skid plate (91) are two spring loaded locking arms (96) and (97) that capture the hitch pin (92). These locking arms (96) and (97), by design, are self-energizing such that as the hitch pin (91) loading increases, the locking arms (96) and (97) close together more tightly. A locking bar (95) is then manually positioned to further prevent the locking arms from opening. Safety chains are not needed with this type of hitch because of the redundancy of this locking bar (95). The electrical connection is manually made with a multi-conductor connector similar to (25) and (26) in FIG. 1.
Referring to FIG. 3, the diagram illustrates a common goose neck (100) type of hitch mechanism. In this system the ball (101) is typically mounted to the middle of pickup truck bed (103) and the socket mechanism (102) is fastened to the trailer frame (110) that reaches up, over and down into the pickup truck bed. Function and connection of these components is similar to that of a standard ball and socket arrangement as shown in FIG. 1.
The current hitch types on the market today have issues with noise, vibration and harshness (NVH) due to their large manufacturing tolerances. The movement between the receiver and the hitch pin results in considerable noise as the pin bumps back and forth in the loose receiver opening. While this is usually not a safety issue, it is uncomfortable and unsettling for the occupants of the vehicle.
During connection to the vehicle it is usually necessary for the driver to have a helper guide the vehicle when backing towards the trailer. Otherwise the driver must get out and keep checking the position of the vehicle. Remotely operated hitch mechanisms are available.
The connection of the trailer to the vehicle may involve the operator to manually push the trailer to a closer alignment position before lowering the trailer with a hand crank or electric jacking device. The connection is secured manually by a locking lever, and a safety pin used to hold the lever down.
The electrical connection is made between the vehicle and the trailer by manually plugging together a multi-conductor connector. This is to provide power for lighting and braking if necessary.